Computer Graphics World

July 2009 57 Gaming n n n n Reuniting the original Ghostbusters cast would have been a waste of time if Ter- minal Reality couldn't capture their like- nesses. Making the task harder, the actors had to be "de-aged" by almost 20 years, to appear as they would have in 1991. Hence, scanning was out of the question. Instead, the team developed a head-sculpting rig in Autodesk's Maya called Adam and Eve. "We first modeled and UV'd generically proportioned male and female heads. We paid attention to the poly count as well as the edge flow so each head could animate properly," says lead animator Angel Gon- zalez. "We then put joints in the head at specific points so we could get some inter- esting shapes." Next, the team grabbed screen shots of the actors from films circa 1991 and im- ported them into Maya. "Since the images come from many angles, we needed to cre- ate a camera system in Maya that allowed the modelers to switch quickly between them to check their modeling progress," explains Gonzalez. "Since it's hard to get a perfect or- thographic (front and profile) view for any actor—most of them have a preferred 'good' side—we would end up with as many as six to 10 cameras on some heads." e model- ers would use all those camera angles to start the sculpting process. e modelers also used a front projec- tion map on each camera's image plane to measure the fidelity of their digital dop- pelganger's face. Once the models were finished, artists imported them into Ado- be's Photoshop, Autodesk's Mudbox, and the Infernal Engine to complete the final material and shader work. Aided by photo- graphs projected directly onto the geom- etry in Maya and baked onto the UVs, the artists painted the face textures in Photo- shop at a resolution of 2048x2048. e textures were used at full resolution in the pre-rendered cinematics, but downsized to 1024 pixels for in-game use. While artists painted most of the tex- tures in Photoshop, they used Infernal for skin shaders, including a subsurface scatter- ing solution. "Since we have so many well- known celebrities in our game, we had to pay special attention to each one. A global solution just didn't work," says Gonzalez. Staying in Character Animating performances that captured the mannerisms and unique energy of each ac- tor—from Peter Venkman's (Bill Murray) deadpan face and slouchy strut, Aykroyd's exuberance, and Ramis's cool-headed se- riousness, to Potts' quirky Janine—was by far the game's most crucial challenge. "When we first heard we were develop- ing the Ghostbusters game, we went from total excitement to instant fear," recalls Gonzalez. "We are making a video game that features five main [and recognizable] characters?" Actually, there were more, all of whom have personalities that fans have grown to love. Because the developers were unable to motion-capture the actual celebrities, they instead found mocap actors who "did their homework in mimicking each character's performance," says Gonzalez. e best act- ing is not limited to the cinematics, how- ever; the in-game animation system gives each ghostbuster access to character-spe- cific animations. For example, when Peter isn't in combat, he strolls around in his sig- nature "slouchy Venkman strut." Nailing that trademark walk and the unique body language of the other actors meant the team had to switch from Auto- desk's 3ds Max to Maya right after the proj- ect was green lit. "We needed more flexibil- ity when it came to making tools and rigs, and to taking advantage of Maya's internal referencing system, which allowed several animators to work on the same rigs across different scenes even before those rigs were finalized," says Gonzalez. is more flex- ible rigging solution, developed in Maya and called Genesis, features on-the-fly FK/ IK switching. It also enables the artists to choose a rig that has a reverse foot setup for hand keyframing or a regular foot set- up for mocap, and uses a single GUI for as many characters as are in the scene. Facial animation would be the true test of success, however. e group spent a lot of pre-production time looking at films star- ring the main characters, and built a pho- neme library in Maya that covered all the nuances of each character. Next, the crew exported those phoneme shapes into OC3 Entertainment's FaceFX for auto-recogni- tion capture from the voice track. Once in- tegrated into Infernal, FaceFX was used to generate the huge volume of dialog lines in The game artists mimicked the trademark movements of the Ghostbusters actors, translating that into the animations, which are a combination of motion capture and hand animation in Maya.

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